The following commit has been merged into the timers/core branch of tip: Commit-ID: 7a35bf2a6a871cd0252cd371d741e7d070b53af9 Gitweb: https://git.kernel.org/tip/7a35bf2a6a871cd0252cd371d741e7d070b53af9 Author: Thomas Gleixner <[email protected]> AuthorDate: Tue, 17 Nov 2020 14:19:47 +01:00 Committer: Thomas Gleixner <[email protected]> CommitterDate: Thu, 19 Nov 2020 10:48:29 +01:00
tick/sched: Optimize tick_do_update_jiffies64() further Now that it's clear that there is always one tick to account, simplify the calculations some more. Signed-off-by: Thomas Gleixner <[email protected]> Link: https://lore.kernel.org/r/[email protected] --- kernel/time/tick-sched.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index ca9191c..306adeb 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -55,7 +55,7 @@ static ktime_t last_jiffies_update; */ static void tick_do_update_jiffies64(ktime_t now) { - unsigned long ticks = 0; + unsigned long ticks = 1; ktime_t delta; /* @@ -93,20 +93,21 @@ static void tick_do_update_jiffies64(ktime_t now) write_seqcount_begin(&jiffies_seq); - last_jiffies_update = ktime_add(last_jiffies_update, tick_period); - delta = ktime_sub(now, tick_next_period); if (unlikely(delta >= tick_period)) { /* Slow path for long idle sleep times */ s64 incr = ktime_to_ns(tick_period); - ticks = ktime_divns(delta, incr); + ticks += ktime_divns(delta, incr); last_jiffies_update = ktime_add_ns(last_jiffies_update, incr * ticks); + } else { + last_jiffies_update = ktime_add(last_jiffies_update, + tick_period); } - do_timer(++ticks); + do_timer(ticks); /* * Keep the tick_next_period variable up to date. WRITE_ONCE()
